U.S. Army Sgt. Bowe Bergdahl went missing from his outpost in Afghanistan in June 2009 and was released by the Taliban on May 31. / U.S. Army via AP

by Jim Michaels, USA TODAY

by Jim Michaels, USA TODAY

WASHINGTON â?? The Army said Monday that it has formally begun its investigation into "the facts and circumstances surrounding the disappearance and capture" of Sgt. Bowe Bergdahl from an outpost in Afghanistan in 2009.

Bergdahl was released from Taliban captivity May 31 in a controversial trade that resulted in handing over five Taliban detainees to the government of Qatar in return for his freedom.

The Army said it appointed Maj. Gen. Kenneth Dahl, an officer with Afghanistan combat experience, to head the probe.

The decision to trade Taliban detainees for Bergdahl's released triggered a storm of criticism from lawmakers who said the agreement reversed America's longstanding policy of not negotiating with terrorists.

The White House has said Bergdahl was a prisoner of war and the United States had to do everything in its power to release him from captivity.

Soldiers who served with Bergdahl said he had left his post without authorization before his capture and the search for him may have placed other troops at risk.

"The primary function of this investigation, as in any other investigation, is to ascertain facts and report them to the appointing authority," the Army statement said.

The Pentagon said its top priority remains Bergdahl's health.

Bergdahl is receiving treatment at a military hospital in San Antonio and will not be interviewed in connection with the investigation "until the reintegration team clears such interaction."

The Army earlier completed an investigation into his disappearance in 2009, and the new team will have access to those documents.